Born 26 October 1829, eldest son of Evan Thomas, Pont-faen, Cellan, Lampeter, and Margaret his wife. He was educated at Mumbles, Swansea, and S. Davids College, Lampeter, matriculating in the University of Oxford from Jesus College, 10 June 1847. He was placed in the 3rd class in classics, took his B.A. in 1851, and M.A. in 1854.

Ordained deacon by bishop Wilberforce of Oxford in 1852 on his college scholarship (he also held a Powis exhibition) he received priest's orders from bishop Bethell of Bangor in 1853. In that year he was curate of Deneio (Pwllheli) and Llannor, and chaplain at Tremadoc, 1854-5. On 13 August 1855, he became perpetual curate of Penmachno and, on 14 March 1860, vicar of S. Ann, Mynydd Llandygài, near Bangor. He remained there for thirty-four years. After a year as vicar of Braunston, Northants, he returned to Wales in August 1895, as vicar of Holyhead. He died 27 December 1905, and was buried at Holyhead.

He was largely instrumental in the foundation of a Welsh church in the settlement in Patagonia, and the first chaplain there, Hugh Davies, was one of his parishioners at S. Ann's. Thomas wrote a number of works in Welsh and English, including a collection of Welsh sermons on the Miracles, and was a constant supporter of the Welsh Church press. He was a canon of Bangor cathedral. In 1871 he married Anna Fison ('Morfudd Eryri'), and their children (two sons and three daughters) were brought up good Welshmen and Welshwomen. One of their sons was the priest and scholar Evan Lorimer Thomas.